In recent years, researchers are paying more attention to high efficiency, high process stability and eco-friendly nanofiber fabrication techniques. Among all of the nanofiber fabrication methods, electrospinning including solution electrospinning and melt electrospinning is the most promising method for nanofiber mass production. Compared to solution electrospinning, melt electrospinning could be applied in many areas such as tissue engineering and wound dressings due to the absence of any toxic solvent involvement. Capillary melt electrospinning generates only one jet with low efficiency. Hence, we have proposed polymer melt differential electrospinning (PMDES) method, which could produce multiple jets with smallest interjet distance of 1.1 mm from an umbrella shape spinneret, thus improving the production efficiency significantly. Many techniques such as material modification, suction wind, and …

Energy and environment are two major problems facing mankind today. Developing environment-friendly and energy-saving technology has always been the focuses of researchers all over the world. Batteries, supercapacitors, and fuel cells are three widely used or promising devices that can ease the energy and environmental pressures. However, there are still many problems and deficiencies that need to be solved or improved, such as low capacity, low-power density, and poor durability. In order to address these drawbacks, nanofibers are introduced into the application of electrode and electrolyte fabrication because of the high specific surface area, interpenetrating network, and strength. This section will introduce the applications of nanofibers in batteries, supercapacitors, and fuel cells in detail.

Magnetic nanofibers (MNFs) are integrated with a variety of properties, such as large surface area, high porosity, small size effect and apparent magnetism. This enables MNFs to possess excellent properties of both nanofibers (NFs) and magnetic materials, which greatly widens the application of the original magnetic materials. A brief review of the properties of MNFs, fabrication techniques, and their emerging applications which include biomedical application, sensing and electronic devices, wastewater treatment and microwave absorption is presented. Finally, the development trend and prospect of MNFs in future are summarized and discussed.

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Melt electrospinning is a technique capable of producing micro-and nanofibers with the advantages of being eco-friendly, cost-effective, and applied in many areas such as nonwovens with high performance, biomedicine, high-efficiency filtration, oil sorption, and many others. This chapter describes the current trends on melt electrospinning including advancements in the technique, processing parameters, materials, apparatus, and areas of applications. Melt differential electrospinning which is a new technique for nanofiber production invented by our innovation team of advanced polymer processing has been introduced. Future perspectives on melt electrospinning are also proposed.

Polyphenylene sulfide (PPS) superfine fiber is a promising high efficient material for high temperature dedusting. In this paper, the PPS superfine fiber was prepared by melt-electrospinning for the first time. In order to produce the finer fibers, the polypropylene (PP) was added to PPS and the effects of blending ratio, spinning voltage, spinning temperature, and spinning distance on resultant fibers were investigated systematically. The superfine fibers of PPS with an average diameter of 4.12 μm were successfully prepared at the optimized condition, which was one third of that by melt-spinning method. With the decrease of 76.21 % fibers diameter, the filter efficiency increased from 87.03 % to 98.05 %. The presented method provides a new way for the scalable and green fabrication of PPS superfine fibers.

Abstract

This article presents yet another methodology for the calculation of dimensionless thermal response factors for vertical borehole ground heat exchanger (GHX) arrays, which is a concept introduced by Eskilson (1987). The presented method is based on a well-known solution to an analogous problem in the field of well hydraulics. This solution method, known mathematically as an incomplete Bessel function, and known in the field of well hydraulics as the 'leaky aquifer function', describes the hydraulic head distribution in an aquifer with predominantly radial flow to a well combined with vertical 'leakage' from geologic layers above and below the pumped aquifer. The solution is adapted to model heat transfer from an array of arbitrarily-placed vertical boreholes of finite depth. With proper expression of parameters in the incomplete Bessel function, we show that g-functions of previous researchers can be approximated. The proposed method has been implemented into Matlab and Excel/VBA for g-function generation and monthly GHX simulation.

Marine Oil spills have become a serious environmental problem, and contribute to severe impacts and economic losses. Fast and efficient cleanup of oil from marine environment is vital. The use of sorbents is one of the most efficient techniques in removing oil from water. In this work, pure polypropylene (PP) ultrafine fibers with 2 μm diameter were prepared by air assisted melt electrospinning device to be used as oil sorbent. Two fiber samples were used in this study, fluffy, cotton like appearance and oriented, cloth like appearance with different porosities. The influence of temperature change on oil/water mixture was studied. Fluffy fibers showed a better performance in sorption capacity. Results indicated that change in temperature was an important factor in determining the sorption capacity of the fibers. Additionally, in contrast to solution electrospinning, melt electrospinning is safer, cost effective and …